David Bain's fight for compensation has hit another hurdle - with Justice Minister Judith Collins ordering a review of recommendations.

It has been widely reported that Canadian Supreme Court judge Ian Binnie concluded Bain was innocent on the balance of probabilities of the murder of his parents, two sisters and brother in 1994. The report has not been released publicly.

Collins has delayed her decision and Prime Minister John Key this morning confirmed Collins has ''some real issues'' with the recommendations, and has sent it to a QC.

''She hasn't been happy with the advice,'' Key told Newstalk ZB. ''I think she's got concerns and said go away and check some of this stuff.''

Key has only seen a ''top line analysis'' of the report - but discussed concerns with Collins.

Cabinet makes the final decision on whether Bain will be compensated for wrongful imprisonment.

Bain spent almost 13 years in jail, and was acquitted at a retrial in 2009.

Former justice minister Simon Power asked Binnie to consider the compensation claim and he reported back in September.

Collins initially said she would make a decision before Christmas. There is speculation Bain stands to get a $2 million payout.

The justice minister is overseas this week and a spokeswoman could only confirm the decision will not go before Cabinet until next year.